Display apparatus having touch driving circuit for generating driving signals for different levels

ABSTRACT

A display apparatus including a display panel, a touch sensing unit including first and second transmission touch lines, and a touch driving circuit to apply first and second touch driving signals to the first and second transmission touch lines, respectively, in which the touch driving circuit includes a first switch group including a first sharing switch device having one end connected to the first transmission touch line, and a second switch group including a second sharing switch device having two ends respectively connected to the second transmission touch line and another end of the first sharing switch device, and the touch driving circuit is configured to turn on the sharing switch devices during a first period such that the touch driving signals have a first voltage level, and turn on the sharing switch devices during a second period such that the touch driving signals have a second voltage level.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.16/058,970 filed on Aug. 8, 2018, which claims priority from and thebenefit of Korean Patent Application No. 10-2017-0123749, filed Sep. 25,2017, each of which is hereby incorporated by reference for all purposesas if fully set forth herein.

BACKGROUND Field

Some exemplary embodiments generally relate to a display apparatus, and,more particularly, to a display apparatus including a touch drivingcircuit.

Discussion

Various display apparatuses, such as a television set, a mobile phone, atablet computer, a navigation unit, a game unit, etc., which are appliedto a multimedia device, have been developed. As an input device of adisplay apparatus, a keyboard or a mouse may be used, however, thedisplay apparatuses include a touch panel as the input device. Ingeneral, a touch sensing function of the touch panel can be continuouslyactivated while the display apparatus is turned on, and, as such, canconsume a lot of power.

The above information disclosed in this section is only forunderstanding the background of the inventive concepts, and, therefore,may contain information that does not form prior art.

SUMMARY

Some exemplary embodiments provide a display apparatus including a touchdriving circuit capable of improving power consumption.

Some exemplary embodiments provide a display apparatus including adisplay panel, a touch sensing unit, and a touch driving circuit.

Additional aspects will be set forth in the detailed description whichfollows, and, in part, will be apparent from the disclosure, or may belearned by practice of the inventive concepts.

According to some exemplary embodiments, a display apparatus includes adisplay panel, a touch sensing unit, and a touch driving circuit. Thetouch sensing unit is disposed on the display panel. The touch sensingunit includes a first transmission touch line and a second transmissiontouch line spaced apart from the first transmission touch line. Thetouch driving circuit is configured to: apply a first touch drivingsignal to the first transmission touch line; and apply a second touchdriving signal to the second transmission touch line. The touch drivingcircuit includes: a first switch group including a first sharing switchdevice of which one end is connected to the first transmission touchline; and a second switch group including a second sharing switch deviceof which one end is connected to the second transmission touch line andanother end is connected to another end of the first sharing switchdevice. The first touch driving signal has a first voltage level duringa first period, and the second touch driving signal has a second voltagelevel different from the first voltage level during the first period.The touch driving circuit is configured to turn on the first sharingswitch device and the second sharing switch device during a secondperiod after the first period such that the first touch driving signaland the second touch driving signal have a voltage level between thefirst voltage level and the second voltage level.

According to some exemplary embodiments, a display apparatus including adisplay panel, a touch sensing unit, and a touch driving circuit. Thetouch sensing unit is disposed on the display panel. The touch sensingunit includes a transmission touch line. The touch driving circuit isconfigured to: receive a driving voltage and a ground voltage; and applya touch driving signal to the transmission touch line. The touch drivingcircuit includes: a switch group including switch devices, the switchdevices including first ends connected to the transmission touch line;and capacitor devices each being connected to second ends of some switchdevices of the switch devices. The touch driving signal has N voltagelevels, a number of the capacitor devices is N−3, and “N” is a naturalnumber greater than or equal to 4.

According to some exemplary embodiments, a display apparatus includes adisplay panel, a touch sensing unit, and a touch driving circuit. Thetouch sensing unit is disposed on the display panel. The touch sensingunit includes a first transmission touch line and a second transmissiontouch line spaced apart from the first transmission touch line. Thetouch driving circuit is configured to: apply a first touch drivingsignal to the first transmission touch line; and apply a second touchdriving signal to the second transmission touch line. The touch drivingcircuit includes: a first switch group including a first sharing switchdevice of which a first end is connected to the first transmission touchline; and a second switch group including a second sharing switch deviceof which a first end is connected to the second transmission touch lineand a second end is connected to a second end of the first sharingswitch device. The touch driving circuit is configured to: turn on thefirst sharing switch device and the second sharing switch device duringa first period such that the first touch driving signal and the secondtouch driving signal have a first voltage level; and turn on the firstsharing switch device and the second sharing switch device during asecond period different from the first period such that the first touchdriving signal and the second touch driving signal have a second voltagelevel different from the first voltage level.

According to some exemplary embodiments, a display apparatus includes adisplay panel, a touch sensing unit, and a touch driving circuit. Thetouch sensing unit is disposed on the display panel. The touch sensingunit includes a first transmission touch line and a second transmissiontouch line spaced apart from the first transmission touch line. Thetouch driving circuit is configured to: apply a first touch drivingsignal to the first transmission touch line; and apply a second touchdriving signal to the second transmission touch line. The first touchdriving signal and the second touch driving signal have first to n-thvoltage levels that sequentially increase, “n” being an odd numbergreater than or equal to 3. Each of the first touch driving signal andthe second touch driving signal has an ((n+1)/2)-th voltage level duringa first period. The first touch driving signal has an ((n+3)/2)-thvoltage level during a second period after the first period. The secondtouch driving signal has an ((n−1)/2)-th voltage level during the secondperiod after the first period.

According to various exemplary embodiments, a touch driving circuit mayapply a touch driving signal, which includes stepwise increasing ordecreasing portions, to transmission touch lines, and, as such, powerconsumption of a touch sensing unit may be reduced. In addition, thenumber of capacitors can be reduced in the touch driving circuit thatgenerates the touch driving signal, and, in this manner, manufacturingcost and time may be reduced.

The foregoing general description and the following detailed descriptionare exemplary and explanatory and are intended to provide furtherexplanation of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the inventive concepts, and are incorporated in andconstitute a part of this specification, illustrate exemplaryembodiments of the inventive concepts, and, together with thedescription, serve to explain principles of the inventive concepts.

FIG. 1 is a perspective view showing a display apparatus according tosome exemplary embodiments.

FIG. 2 is a cross-sectional view showing a display apparatus accordingto some exemplary embodiments.

FIG. 3 is a plan view showing a touch flexible printed circuit board onwhich a touch sensing unit and a touch driving chip shown in FIG. 2 aremounted according to some exemplary embodiments.

FIG. 4 is a circuit diagram showing a touch driving circuit andtransmission touch lines according to some exemplary embodiments.

FIGS. 5A, 5B, 5C, 5D, 5E, 5F, 5G, 5H, and 5I are views sequentiallyshowing operational processes of the touch driving circuit of FIG. 4used to generate a touch driving signal having a plurality of voltagelevels according to some exemplary embodiments.

FIG. 6 is waveform diagram showing switching signals applied to first totenth switching devices and a touch driving signal according to someexemplary embodiments.

FIG. 7A is a view showing a waveform of a touch driving signal during areference period according to a comparative example.

FIG. 7B is a view showing a loss amount of electric charges in atransmission touch line due to the touch driving signal of FIG. 7A as afunction of a charge amount of a load capacitor.

FIG. 7C is a view showing an amount of electric charges discharged fromthe load capacitor due to the touch driving signal of FIG. 7A.

FIG. 7D is a view showing a sum of a loss amount of electric charges inthe transmission touch line due to the touch driving signal of FIG. 7Aand the amount of the electric charges discharged from the loadcapacitor.

FIG. 8A is a view showing a waveform of a touch driving signal during areference period according to some exemplary embodiments.

FIG. 8B is a view showing a loss amount of electric charges in atransmission touch line due to the touch driving signal of FIG. 8A as afunction of a charge amount of a load capacitor according to someexemplary embodiments.

FIG. 8C is a view showing an amount of electric charges discharged fromthe load capacitor due to the touch driving signal of FIG. 8A accordingto some exemplary embodiments.

FIG. 8D is a view showing a sum of a loss amount of electric charges inthe transmission touch line due to the touch driving signal of FIG. 8Aand the amount of the electric charges discharged from the loadcapacitor according to some exemplary embodiments.

FIG. 9 is a circuit diagram showing a touch driving circuit andtransmission touch lines according to some exemplary embodiments.

FIG. 10 is a waveform diagram showing a waveform of a touch drivingsignal according to according to some exemplary embodiments.

FIG. 11 is a waveform diagram showing a waveform of a touch drivingsignal according to according to some exemplary embodiments.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

In the following description, for the purposes of explanation, numerousspecific details are set forth in order to provide a thoroughunderstanding of various exemplary embodiments. It is apparent, however,that various exemplary embodiments may be practiced without thesespecific details or with one or more equivalent arrangements. In otherinstances, well-known structures and devices are shown in block diagramform in order to avoid unnecessarily obscuring various exemplaryembodiments. Further, various exemplary embodiments may be different,but do not have to be exclusive. For example, specific shapes,configurations, and characteristics of an exemplary embodiment may beimplemented in another exemplary embodiment without departing from thespirit and the scope of the disclosure.

Unless otherwise specified, the illustrated exemplary embodiments are tobe understood as providing exemplary features of varying detail of someexemplary embodiments. Therefore, unless otherwise specified, thefeatures, components, modules, layers, films, panels, regions, aspects,etc. (hereinafter individually or collectively referred to as“elements”), of the various illustrations may be otherwise combined,separated, interchanged, and/or rearranged without departing from thespirit and the scope of the disclosure.

The use of cross-hatching and/or shading in the accompanying drawings isgenerally provided to clarify boundaries between adjacent elements. Assuch, neither the presence nor the absence of cross-hatching or shadingconveys or indicates any preference or requirement for particularmaterials, material properties, dimensions, proportions, commonalitiesbetween illustrated elements, and/or any other characteristic,attribute, property, etc., of the elements, unless specified. Further,in the accompanying drawings, the size and relative sizes of elementsmay be exaggerated for clarity and/or descriptive purposes. When anexemplary embodiment may be implemented differently, a specific processorder may be performed differently from the described order. Forexample, two consecutively described processes may be performedsubstantially at the same time or performed in an order opposite to thedescribed order. Also, like reference numerals denote like elements.

When an element is referred to as being “on,” “connected to,” or“coupled to” another element, it may be directly on, connected to, orcoupled to the other element or intervening elements may be present.When, however, an element is referred to as being “directly on,”“directly connected to,” or “directly coupled to” another element, thereare no intervening elements present. To this end, the term “connected”may refer to physical, electrical, and/or fluid connection. Further, theD1-axis, the D2-axis, and the D3-axis are not limited to three axes of arectangular coordinate system, and may be interpreted in a broadersense. For example, the D1-axis, the D2-axis, and the D3-axis may beperpendicular to one another, or may represent different directions thatare not perpendicular to one another. For the purposes of thisdisclosure, “at least one of X, Y, and Z” and “at least one selectedfrom the group consisting of X, Y, and Z” may be construed as X only, Yonly, Z only, or any combination of two or more of X, Y, and Z, such as,for instance, XYZ, XYY, YZ, and ZZ. As used herein, the term “and/or”includes any and all combinations of one or more of the associatedlisted items.

Although the terms “first,” “second,” etc. may be used herein todescribe various elements, these elements should not be limited by theseterms. These terms are used to distinguish one element from anotherelement. Thus, a first element discussed below could be termed a secondelement without departing from the teachings of the disclosure.

Spatially relative terms, such as “beneath,” “below,” “under,” “lower,”“above,” “upper,” “over,” “higher,” “side” (e.g., as in “sidewall”), andthe like, may be used herein for descriptive purposes, and, thereby, todescribe one element's relationship to another element(s) as illustratedin the drawings. Spatially relative terms are intended to encompassdifferent orientations of an apparatus in use, operation, and/ormanufacture in addition to the orientation depicted in the drawings. Forexample, if the apparatus in the drawings is turned over, elementsdescribed as “below” or “beneath” other elements or features would thenbe oriented “above” the other elements or features. Thus, the exemplaryterm “below” can encompass both an orientation of above and below.Furthermore, the apparatus may be otherwise oriented (e.g., rotated 90degrees or at other orientations), and, as such, the spatially relativedescriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particularembodiments and is not intended to be limiting. As used herein, thesingular forms, “a,” “an,” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise. Moreover,the terms “comprises,” “comprising,” “includes,” and/or “including,”when used in this specification, specify the presence of statedfeatures, integers, steps, operations, elements, components, and/orgroups thereof, but do not preclude the presence or addition of one ormore other features, integers, steps, operations, elements, components,and/or groups thereof. It is also noted that, as used herein, the terms“substantially,” “about,” and other similar terms, are used as terms ofapproximation and not as terms of degree, and, as such, are utilized toaccount for inherent deviations in measured, calculated, and/or providedvalues that would be recognized by one of ordinary skill in the art.

Various exemplary embodiments are described herein with reference tosectional and/or exploded illustrations that are schematic illustrationsof idealized exemplary embodiments and/or intermediate structures. Assuch, variations from the shapes of the illustrations as a result, forexample, of manufacturing techniques and/or tolerances, are to beexpected. Thus, exemplary embodiments disclosed herein should not beconstrued as limited to the particular illustrated shapes of regions,but are to include deviations in shapes that result from, for instance,manufacturing. In this manner, regions illustrated in the drawings areschematic in nature and shapes of these regions may not illustrate theactual shapes of regions of a device, and, as such, are not intended tobe limiting.

As customary in the field, some exemplary embodiments are described andillustrated in the accompanying drawings in terms of functional blocks,units, and/or modules. Those skilled in the art will appreciate thatthese blocks, units, and/or modules are physically implemented byelectronic (or optical) circuits, such as logic circuits, discretecomponents, microprocessors, hard-wired circuits, memory elements,wiring connections, and the like, which may be formed usingsemiconductor-based fabrication techniques or other manufacturingtechnologies. In the case of the blocks, units, and/or modules beingimplemented by microprocessors or other similar hardware, they may beprogrammed and controlled using software (e.g., microcode) to performvarious functions discussed herein and may optionally be driven byfirmware and/or software. It is also contemplated that each block, unit,and/or module may be implemented by dedicated hardware, or as acombination of dedicated hardware to perform some functions and aprocessor (e.g., one or more programmed microprocessors and associatedcircuitry) to perform other functions. Also, each block, unit, and/ormodule of some exemplary embodiments may be physically separated intotwo or more interacting and discrete blocks, units, and/or moduleswithout departing from the spirit and scope of the inventive concepts.Further, the blocks, units, and/or modules of some exemplary embodimentsmay be physically combined into more complex blocks, units, and/ormodules without departing from the spirit and scope of the inventiveconcepts.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure is a part. Terms,such as those defined in commonly used dictionaries, should beinterpreted as having a meaning that is consistent with their meaning inthe context of the relevant art and will not be interpreted in anidealized or overly formal sense, unless expressly so defined herein.

FIG. 1 is a perspective view showing a display apparatus according tosome exemplary embodiments.

Referring to FIG. 1, a display apparatus EA may be, but is not limitedto, a touch screen apparatus. The touch screen apparatus may be at leastone of a smartphone, a tablet personal computer, a mobile phone, anelectronic book (e-book) reader, a notebook computer, a personal digitalassistant (PDA), a portable multimedia player (PMP), an MP3 player, amobile medical device, a camera, and a wearable display device; however,exemplary embodiments are not limited thereto.

The display apparatus EA provides a touch screen surface TCS. The touchscreen surface TCS corresponds to an outermost surface of the displayapparatus EA, is exposed to the outside to provide a user with an image(e.g., image IM), and corresponds to a target surface for an externalinput TC.

The touch screen surface TCS displays the image IM to provide the userwith information or to communicate with the user. In addition, the touchscreen surface TCS senses the external input TC. In various exemplaryembodiments, the external input TC indicates a user's hand, but itshould not be limited to the user's hand. That is, the external input TCmay be an input generated by a stylus pen or a hovering input dependingon a sensing device included in the display apparatus EA.

The display apparatus EA may have various exteriors. As an example, thedisplay apparatus EA may include short sides extending in a firstdirection DR1 and long sides extending in a second direction DR2. Athird direction DR3 indicates a thickness direction of the displayapparatus EA.

FIG. 2 is a cross-sectional view showing the display apparatus EAaccording to some exemplary embodiments. That is, FIG. 2 shows across-section defined by the second direction DR2 and the thirddirection DR3.

The display apparatus EA includes a display panel DP, a touch sensingunit TS, a touch flexible printed circuit board (touch FPC) TFP, a touchdriving chip TIC, and a printed circuit board PCB. Although not shownseparately, the display apparatus EA may further include a protectivemember disposed under the display panel DP, an anti-reflection member,and/or a window member disposed on the touch sensing unit TS.

The display panel DP may display the image IM. The display panel DP maybe one of an organic light emitting display panel, a liquid crystaldisplay panel, a plasma display panel, an electrophoretic display panel,and an electrowetting display panel. Hereinafter, the organic lightemitting display panel will be described as the display panel DP.

The touch sensing unit TS obtains coordinate information about theexternal input TC. The touch sensing unit TS is disposed on the displaypanel DP. The touch sensing unit TS may be provided as an independentmodule and attached to the display panel DP by an adhesive layer.According to some exemplary embodiments, the touch sensing unit TS maybe attached to the display panel DP without using a separate adhesiveand formed through consecutive processes of the display panel DP. Forexample, the touch sensing unit TS may be grown on (or as part of) alayer of the display panel DP.

The touch sensing unit TS may have a multi-layer structure. The touchsensing unit TS may include a single conductive layer or a plurality ofconductive layers. The touch sensing unit TS may include a singleinsulating layer or a plurality of insulating layers.

The touch FPC TFP is electrically connected to the touch sensing unitTS. The touch FPC TFP includes lines to electrically connect the touchdriving chip TIC to the touch sensing unit TS. The touch FPC TFPincludes a flexible material, and thus, the touch FPC TFP may be bent.The touch FPC TFP is downwardly bent, and thus, the printed circuitboard PCB is disposed on a rear side of the display panel DP. In FIG. 2,the touch FPC TFP is attached to an upper surface of the touch sensingunit TS, but it should not be limited thereto or thereby. For instance,the touch FPC TFP may be attached to the display panel DP, and thedisplay panel DP may be electrically connected to the touch sensing unitTS.

The touch driving chip TIC may be mounted on the touch FPC TFP, but itshould not be limited thereto or thereby. According to some exemplaryembodiments, the touch driving chip TIC may be mounted on the displaypanel DP. The touch driving chip TIC may include at least a portion of atouch driving circuit. The touch driving circuit includes a plurality ofelectronic devices and lines. The touch driving circuit provides a touchdriving signal to drive the touch sensing unit TS and receives a sensingsignal from the touch sensing unit TS. The touch driving circuitincludes a switching device and generates the touch driving signalhaving a plurality of levels, the details of which will be describedlater.

The printed circuit board PCB is connected to the touch FPC TFP. Theprinted circuit board PCB may receive the sensing signal from the touchdriving chip TIC and provide a power voltage to generate the touchdriving signal.

Although not shown in the figures, the display apparatus EA may furtherinclude a flexible printed circuit board connected to the display panelDP. The flexible printed circuit board may provide a signal to drive thedisplay panel DP.

FIG. 3 is a plan view showing a touch flexible printed circuit board onwhich a touch sensing unit and a touch driving chip shown in FIG. 2 aremounted according to some exemplary embodiments.

The touch sensing unit TS may be implemented in an electrostaticcapacitance manner. The touch sensing unit TS may be operated in one ofa manner that extracts (or otherwise determines) touch coordinates basedon a variation in capacitance of a capacitor formed by two touch linesextending in different directions from each other and insulated fromeach other, and a manner that extracts (or otherwise determines) thetouch coordinates based on a variation in capacitance of a capacitorformed by touch electrodes arranged in an active area. In the followingexemplary embodiments, the touch sensing unit TS operated in the formermanner will be described as a representative example.

The touch sensing unit TS may be divided into an active area AA2 and aperipheral area NAA2. The touch sensing unit TS senses a touch input inthe active area AA2 and does not sense the touch input in the peripheralarea NAA2.

The touch sensing unit TS may include a base layer TBL, transmissiontouch lines TX1 to TX5, sensing touch lines RX1 to RX4, transmissionlines TL1 to TL5, sensing lines RL1 to RL4, and touch pads TPD.

Each of the transmission touch lines TX1 to TX5 includes a plurality oftransmission touch sensor parts SP1 and a plurality of first connectionparts CP1. The transmission touch sensor parts SP1 are arranged in thefirst direction DR1. Each of the first connection parts CP1 connects twotransmission touch sensor parts SP1 adjacent to each other among thetransmission touch sensor parts SP1. Although not shown in the figures,each of the transmission touch sensor parts SP1 may have a mesh shapethrough which openings are defined.

The sensing touch lines RX1 to RX4 are insulated from the transmissiontouch lines TX1 to TX5 while crossing the transmission touch lines TX1to TX5. Each of the sensing touch lines RX1 to RX4 includes a pluralityof sensing touch sensor parts SP2 and a plurality of second connectionparts CP2. The sensing touch sensor parts SP2 are arranged in the seconddirection DR2. Each of the second connection parts CP2 connects twosensing touch sensor parts SP2 adjacent to each other among the sensingtouch sensor parts SP2. Although not shown in the figures, each of thesensing touch sensor parts SP2 may have a mesh shape through whichopenings are defined.

In some exemplary embodiments, the transmission touch sensor parts SP1and the first connection parts CP1 are disposed on a first layer, andthe sensing touch sensor parts SP2 and the second connection parts CP2are disposed on a second layer different from the first layer. Accordingto another exemplary embodiment, the transmission touch sensor partsSP1, the first connection parts CP1, and the sensing touch sensor partsSP2 may be disposed on the first layer, and the second connection partsSP2 may be disposed on the second layer different from the first layer,or vice versa.

The transmission touch lines TX1 to TX5 and the sensing touch lines RX1to RX4 form touch capacitors. The touch sensing unit TS may sense touchinput coordinates based on a variation of the touch capacitors.

One ends (or first ends) of the transmission lines TL1 to TL5 may beconnected to the transmission touch lines TX1 to TX5. The other ends (orsecond ends) of the transmission lines TL1 to TL5 may be connected tothe touch pads TPD. The transmission lines TL1 to TL5 may apply thetouch driving signal received from the touch driving chip TIC throughthe touch pads TPD to the transmission touch lines TX1 to TX5.

One ends (or first ends) of the sensing lines RL1 to RL4 may beconnected to the sensing touch lines RX1 to RX4. The other ends (orsecond ends) of the sensing lines RL1 to RL4 may be connected to thetouch pads TPD. The sensing lines RL1 to RL4 may apply the sensingsignals from the sensing touch lines RX1 to RX4 to the touch drivingchip TIC through the touch pads TPD.

FIG. 4 is a circuit diagram showing a touch driving circuit andtransmission touch lines according to some exemplary embodiments.

That is, FIG. 4 shows first and second transmission touch lines TX1 andTX2 among the transmission touch lines, and a portion of the touchdriving circuit TDC that drives the two transmission touch lines TX1 andTX2 as a representative example. Although not shown in the figures, thetouch driving circuits TDC respectively connected to the transmissiontouch lines TX1 to TX5 of FIG. 3 have the same circuit configuration asthat of the touch driving circuit TDC shown in FIG. 4.

In FIG. 4, the first transmission touch line TX1 is modeled with anequivalent circuit that includes a first resistor R1 and a first loadcapacitor CL1. The first resistor R1 may indicate a line resistance ofthe first transmission touch line TX1, and the first load capacitor CL1may indicate a capacitor formed by a line and an electrode around theline (e.g., an upper cathode electrode of an organic light emittingdisplay panel). Similarly, the second transmission touch line TX2 ismodeled with an equivalent circuit that includes a second resistor R2and a second load capacitor CL2.

The touch driving circuit TDC may include switch groups SWA and SWBelectrically and respectively connected to the transmission touch linesTX1 and TX2 and capacitor devices CAP1 and CAP2.

The touch driving circuit TDC receives a driving voltage VD from anexternal source, for example, the printed circuit board PCB of FIG. 2,and is grounded. The touch driving circuit TDC receives the drivingvoltage VD and generates the touch driving signal having a plurality ofvoltage levels using the switch groups SWA and SWB and the capacitordevices CAP1 and CAP2.

The touch driving circuit TDC generates a first touch driving signal,which is provided to the first transmission touch line TX1 and a secondtouch driving signal, which is provided to the second transmission touchline TX2. The first touch driving signal may be a signal measured at afirst node N1 of FIG. 4 and may be measured at an output terminal of thetouch driving chip TIC of FIG. 2. The second touch driving signal may bea signal measured at a second node N2 of FIG. 4 and may be measured atan output terminal of the touch driving chip TIC of FIG. 2.

Hereinafter, the touch driving circuit TDC that generates the touchdriving signal having four voltage levels will be described in detail asa representative example.

The switch groups SWA and SWB include a first switch group SWA connectedto the first transmission touch line TX1, and a second switch group SWBconnected to the second transmission touch line TX2. The switch groupsSWA and SWB may be included in the touch driving chip TIC of FIG. 2.

The first switch group SWA and the second switch group SWB may beindependently controlled from each other. The switch devices included inthe switch groups SWA and SWB may be implemented in (or as) transistors.

The capacitor devices CAP1 and CAP2 may include a first capacitor deviceCAP1 and a second capacitor device CAP2. The first and second capacitordevices CAP1 and CAP2 have a capacitance greater than that of the firstand second load capacitors CL1 and CL2 of the first and secondtransmission touch lines TX1 and TX2. The capacitor devices CAP1 andCAP2 may be included in the touch driving chip TIC of FIG. 2 and/or maybe included in the printed circuit board PCB of FIG. 2.

In order to receive the driving voltage VD and generate N voltagelevels, the number of the switch devices included in each of the switchgroups SWA and SWB may be “N+1”, and the number of the capacitor devicesmay be “N−2,” with N being an integer greater than zero. Detaileddescriptions of the above will be described later.

The first switch group SWA may include first, second, third, fourth, andfifth switch devices SW11, SW12, SW13, SW14, and SW15. One end (or afirst end) of each of the first to fifth switch devices SW11 to SW15 maybe connected to the first transmission touch line TX1. The other end (orsecond end) of the first switch device SW11 is connected to a groundterminal. The first switch device SW11 may be referred to as a “firstground switch device.” The other (or second) end of the second switchdevice SW12 is connected to one electrode of the first capacitor deviceCAP1. The second switch device SW12 may be referred to as a “first lowerswitch device.” The other (or second) end of the third switch deviceSW13 is connected to the other (or second) end of an eighth switchdevice SW23. The third switch device SW13 may be referred to as a “firstsharing switch device.” The other (or second) end of the fourth switchdevice SW14 is connected to one electrode of the second capacitor deviceCAP2. The fourth switch device SW14 may be referred to as a “first upperswitch device.” The other (or second) end of the fifth switch deviceSW15 receives the driving voltage VD. The fifth switch device SW15 maybe referred to as a “first driving switch device,”

The second switch group SWB includes sixth, seventh, eighth, ninth, andtenth switch devices SW21, SW22, SW23, SW24, and SW25. One end (or afirst end) of each of the sixth to tenth switch devices SW21 to SW25 isconnected to the second transmission touch line TX2, and the other (orsecond) end of each of the sixth to tenth switch devices SW21 to SW25 isconnected to the other end of each of the first to fifth switch devicesSW11 to SW15. The other (or second) end of the sixth switch device SW21is connected to the ground terminal. The sixth switch device SW21 may bereferred to as a “second ground switch device.” The other (or second)end of the seventh switch device SW22 is connected to the one electrodeof the first capacitor device CAP1. The seventh switch device SW22 maybe referred to as a “second lower switch device.” The other (or second)end of the eighth switch device SW23 is connected to the other end ofthe third switch device SW13. The eighth switch device SW23 may bereferred to as a “second sharing switch device.” The other (or second)end of the ninth switch device SW24 connected to the one electrode ofthe second capacitor device CAP2. The ninth switch device SW24 may bereferred to as a “second upper switch device.” The other (or second) endof the tenth switch device SW25 receives the driving voltage VD. Thetenth switch device SW25 may be referred to as a “second driving switchdevice.”

The one electrode of the first capacitor device CAP1 is connected to theother end of the second switch device SW12 and the other end of theseventh switch device SW22, and the other electrode of the firstcapacitor device CAP1 is connected to the ground terminal. The oneelectrode of the second capacitor device CAP2 is connected to the otherend of the fourth switch device SW14 and the other end of the ninthswitch device SW24, and the other electrode of the second capacitordevice CAP2 is connected to the ground terminal.

FIGS. 5A, 5B, 5C, 5D, 5E, 5F, 5G, 5H, and 5I are views sequentiallyshowing operational processes of the touch driving circuit of FIG. 4used to generate a touch driving signal having a plurality of voltagelevels according to some exemplary embodiments. FIG. 6 is waveformdiagram showing switching signals applied to first to tenth switchingdevices and a touch driving signal according to some exemplaryembodiments.

The switch signals include first to fifth switch signals SG11 to SG15and sixth to tenth switch signals SG21 to SG25 respectively applied tothe first to fifth switch devices SW11 to SW15 and the sixth to tenthswitch devices SW21 to SW25. The first to fifth switch devices SW11 toSW15 and the sixth to tenth switch devices SW21 to SW25 may be turned onduring a period in which the first to fifth switch signals SG11 to SG15and the sixth to tenth switch signals SG21 to SG25 have a high level,and the first to fifth switch devices SW11 to SW15 and the sixth totenth switch devices SW21 to SW25 may be turned off during a period inwhich the first to fifth switch signals SG11 to SG15 and the sixth totenth switch signals SG21 to SG25 have a low level.

In the following descriptions, the touch driving circuit TDC generates afirst touch driving signal SG1 applied to the first transmission touchline TX1 and generates a second touch driving signal SG2 applied to thesecond transmission touch line TX2. The first touch driving signal SG1and the second touch driving signal SG2 may have different phases fromeach other. For instance, the first touch driving signal SG1 and thesecond touch driving signal SG2 may have opposite phases to each other,e.g., 180° out of phase from each other.

The first and second touch driving signals SG1 and SG2 may be astep-shaped signal that repeatedly rises and falls. In some exemplaryembodiments, the first and second touch driving signals SG1 and SG2repeatedly rise and fall between a first level V1 that is a groundvoltage level, and a fifth level V5 that is a voltage level of thedriving voltage VD. To this end, the first, second, third, fourth, andfifth switch devices SW11, SW12, SW13, SW14, and SW15 are turned onsequentially or in reverse order, and sixth, seventh, eighth, ninth, andtenth switch devices SW21, SW22, SW23, SW24, and SW25 are turned onsequentially or in reverse order. FIG. 6 shows the first and secondtouch driving signals SG1 and SG2 in analog voltage form by taking intoaccount a delay occurring in a portion of the first and second touchdriving signals SG1 and SG2.

Referring to FIGS. 5A and 6, the third switch device SW13 is turned onin response to a third switch signal SG13 during a first period PR1, andthe eighth switch device SW23 is turned on in response to an eighthswitch signal SG23 during the first period PR1. The other switch devicesSW11, SW12, SW14, SW15, SW21, SW22, SW24, and SW25 are turned off duringthe first period PR1.

The first load capacitor CL1 of the first transmission touch line TX1shares electric charges with the second load capacitor CL2 of the secondtransmission touch line TX2, and a voltage level of the first touchdriving signal SG1 becomes equal to a voltage level of the second touchdriving signal SG2. During the first period PR1, the first touch drivingsignal SG1 and the second touch driving signal SG2 may have a thirdlevel V3. The third level V3 may be approximate to an intermediate valuebetween the first level V1 and the fifth level V5.

Referring to FIGS. 5B and 6, the fourth switch device SW14 is turned onin response to a fourth switch signal SG14 during a second period PR2,and the seventh switch device SW22 is turned on in response to a seventhswitch signal SG22 during the second period PR2. The other switchdevices SW11, SW12, SW13, SW15, SW21, SW23, SW24, and SW25 are turnedoff during the second period PR2.

An electric potential of a third node N3 to which the one electrode ofthe first capacitor device CAP1 is connected may have a second level V2.In addition, an electric potential of a fourth node N4 to which the oneelectrode of the second capacitor device CAP2 is connected may have afourth level V4.

A voltage level of the first touch driving signal SG1 corresponds to thethird level V3 right after the first period PR1, and a voltage level ofthe fourth node N4 corresponds to the fourth level V4 right after thefirst period PR1. The first load capacitor CL1 is charged with electriccharges charged in the second capacitor CAP2 during the second periodPR2, and thus, the voltage level of the first touch driving signal SG1increases to the fourth level V4. Since the capacitance of the secondcapacitor device CAP2 is set to be at least ten to hundred times greaterthan that of the first load capacitor CL1, a variation in voltage levelof the fourth node N4 is very small even though the first load capacitorCL1 is charged with the electric charges. As such, the variation involtage level of the fourth node N4 may be disregarded.

A voltage level of the second touch driving signal SG2 corresponds tothe third level V3 right after the first period PR1, and a voltage levelof the third node N3 corresponds to the second level V2 right after thefirst period PR1. The first capacitor device CAP1 discharges the secondload capacitor CL2 during the second period PR2, and thus, the voltagelevel of the second touch driving signal SG2 reaches the second levelV2. Since the capacitance of the first capacitor device CAP1 is set tobe at least ten to hundred times greater than that of the second loadcapacitor CL2, a variation in voltage level of the third node N3 is verysmall even though the electric charges in the second load capacitor CL2are discharged. As such, the variation in voltage level of the thirdnode N3 may be disregarded.

Referring to FIGS. 5C and 6, the fifth switch device SW15 is turned onin response to a fifth switch signal SG15 during a third period PR3, andthe sixth switch device SW21 is turned on in response to a sixth switchsignal SG21 during the third period PR3. The other switch devices SW11,SW12, SW13, SW14, SW22, SW23, SW24, and SW25 are turned off during thethird period PR3.

During the third period PR3, the voltage level of the first touchdriving signal SG1 reaches the fifth level V5 by the driving voltage VD.The voltage level of the second touch driving signal SG2 reaches thefirst level V1 by the ground voltage during the third period PR3.

Referring to FIGS. 5D and 6, the fourth switch device SW14 is turned onin response to the fourth switch signal SG14 during a fourth period PR4,and the seventh switch device SW22 is turned on in response to theseventh switch signal SG22 during the fourth period PR4. The otherswitch devices SW11, SW12, SW13, SW15, SW21, SW23, SW24, and SW25 areturned off during the fourth period PR4.

The voltage level of the first touch driving signal SG1 corresponds tothe fifth level V5 right after the third period PR3, and the voltagelevel of the fourth node N4 corresponds to the fourth level V4 rightafter the third period PR3. During the fourth period PR4, the secondcapacitor device CAP2 discharges the first load capacitor CL1, and thus,the first touch driving signal SG1 reaches the fourth level V4.

The voltage level of the second touch driving signal SG2 corresponds tothe first level V1 right after the third period PR3, and the voltagelevel of the third node N3 corresponds to the second level V2 rightafter the third period PR3. During the fourth period PR4, the firstcapacitor device CAP1 charges the second load capacitor CL2, and thus,the second touch driving signal SG2 reaches the second level V2.

Referring to FIGS. 5E and 6, the third switch device SW13 is turned onin response to the third switch signal SG13 during a fifth period PR5,and the eighth switch device SW23 is turned on in response to the eighthswitch signal SG23 during the fifth period PR5. The other switch devicesSW11, SW12, SW14, SW15, SW21, SW22, SW24, and SW25 are turned off duringthe fifth period PR5.

The first load capacitor CL1 of the first transmission touch line TX1shares electric charges with the second load capacitor CL2 of the secondtransmission touch line TX2, and the voltage level of the first touchdriving signal SG1 becomes equal to the voltage level of the secondtouch driving signal SG2. During the fifth period PR5, the first touchdriving signal SG1 and the second touch driving signal SG2 may have thethird level V3. The third level V3 may approximate to the intermediatevalue between the first level V1 and the fifth level V5.

Referring to FIGS. 5F and 6, the second switch device SW12 is turned onin response to the second switch signal SG12 during a sixth period PR6,and the ninth switch device SW24 is turned on in response to a ninthswitch signal SG24 during the sixth period PR6. The other switch devicesSW11, SW13, SW14, SW15, SW21, SW22, SW23, and SW25 are turned off duringthe sixth period PR6.

The voltage level of the first touch driving signal SG1 corresponds tothe third level V3 right after the fifth period PR5, and the voltagelevel of the third node N3 corresponds to the second level V2 rightafter the fifth period PR5. During the sixth period PR6, the firstcapacitor device CAP1 discharges the first load capacitor CL1, and thus,the first touch driving signal SG1 reaches the second level V2.

The voltage level of the second touch driving signal SG2 corresponds tothe third level V3 right after the fifth period PR5, and the voltagelevel of the fourth node N4 corresponds to the fourth level V4 rightafter the fifth period PR5. During the sixth period PR6, the secondcapacitor device CAP2 charges the second load capacitor CL2, and thus,the second touch driving signal SG2 reaches the fourth level V4.

Referring to FIGS. 5G and 6, the first switch device SW11 is turned onin response to the first switch signal SG11 during a seventh period PR7,and the tenth switch device SW25 is turned on in response to a tenthswitch signal SG25 during the seventh period PR7. The other switchdevices SW12, SW13, SW14, SW15, SW21, SW22, SW23, and SW24 are turnedoff during the seventh period PR7.

During the seventh period PR7, the voltage level of the first touchdriving signal SG1 reaches the first level V1 by the ground voltage.During the seventh period PR7, the voltage level of the second touchdriving signal SG2 reaches the fifth level V5 by the driving voltage VD.

Referring to FIGS. 5H and 6, the second switch device SW12 is turned onin response to the second switch signal SG12 during an eighth periodPR8, and the ninth switch device SW24 is turned on in response to theninth switch signal SG24 during the eighth period PR8. The other switchdevices SW11, SW13, SW14, SW15, SW21, SW22, SW23, and SW25 are turnedoff during the eight period PR8.

The voltage level of the first touch driving signal SG1 corresponds tothe first level V1 right after the seventh period PR7, and the voltagelevel of the third node N3 corresponds to the second level V2 rightafter the seventh period PR7. During the eighth period PR8, the firstcapacitor device CAP1 charges the first load capacitor CL1, and thus,the first touch driving signal SG1 reaches the second level V2.

The voltage level of the second touch driving signal SG2 corresponds tothe fifth level V5 right after the seventh period PR7, and the voltagelevel of the fourth node N4 corresponds to the fourth level V4 rightafter the seventh period PR7. During the eighth period PR8, the secondcapacitor device CAP2 discharges the second load capacitor CL2, andthus, the second touch driving signal SG2 reaches the fourth level V4.

Referring to FIGS. 5I and 6, the third switch device SW13 is turned onin response to the third switch signal SG13 during a ninth period PR9,and the eighth switch device SW23 is turned on in response to the eighthswitch signal SG23 during the ninth period PR9. The other switch devicesSW11, SW12, SW14, SW15, SW21, SW22, SW24, and SW25 are turned off duringthe ninth period PR9.

The first load capacitor CL1 of the first transmission touch line TX1shares electric charges with the second load capacitor CL2 of the secondtransmission touch line TX2, and the voltage level of the first touchdriving signal SG1 becomes equal to the voltage level of the secondtouch driving signal SG2. During the ninth period PR9, the first touchdriving signal SG1 and the second touch driving signal SG2 may have thethird level V3. The third level V3 may approximate to the intermediatevalue between the first level V1 and the fifth level V5.

The touch driving circuit TDC may generate the first and second touchdriving signals SG1 and SG2 corresponding to one cycle by sequentiallyrunning processes as exemplarily shown in FIGS. 5A to 5I.

In the above description, the first touch driving signal SG1 and thesecond touch driving signal SG2 have opposite phases to each other, butthey are not limited thereto or thereby. That is, since the first switchgroup SWA and the second switch group SWB may be independentlycontrolled from each other, the first touch driving signal SG1 and thesecond touch driving signal SG2 may have the same phase as each other oropposite phases to each other.

In a case that the electric charges in the transmission touch lines arenot shared during a specific period, at least N−2 capacitor devices areused to generate the touch driving signal having the N voltage levels.According to some exemplary embodiments, N−3 capacitor devices (e.g.,two capacitor devices as described herein) are used to generate thetouch driving signal having the N voltage levels (e.g., the first tofifth levels V1 to V5 as exemplarily described herein) by sharing theelectric charges of the transmission touch lines during the specificperiod. In this case, the “N” may be a natural number equal to orgreater than 4.

Since the capacitor device has a relatively large capacitance, thecapacitor device occupies a large area, a degree of freedom in designingdecreases due to the large area, and a manufacturing cost increases.According to various exemplary embodiments, the number of capacitordevices may be reduced. Thus, the manufacturing cost may be reduced, andthe degree of freedom in designing may be improved.

FIG. 7A is a view showing a waveform of a touch driving signal during areference period according to a comparative example. FIG. 7B is a viewshowing a loss amount of electric charges in a transmission touch linedue to the touch driving signal of FIG. 7A as a function of a chargeamount of a load capacitor. FIG. 7C is a view showing an amount ofelectric charges discharged from the load capacitor due to the touchdriving signal of FIG. 7A. FIG. 7D is a view showing a sum of a lossamount of electric charges in the transmission touch line due to thetouch driving signal of FIG. 7A and the amount of the electric chargesdischarged from the load capacitor.

The touch driving circuit according to the comparative example providesa square-wave voltage signal, which has a driving voltage as its highestlevel as shown in FIG. 7A, as a touch driving signal SGA withoutincluding the switch group and the capacitor device. In FIG. 7A, a firstlevel V1 and a fifth level V5 are assumed to be the same as the firstlevel V1 and the fifth level V5 shown in FIG. 6, respectively, and areference period PR is assumed to be the same as the fourth period PR4to the seventh period PR7 shown in FIG. 6.

Referring to FIGS. 7A and 7B, since the touch driving signal SGA has thefifth level V5 corresponding to the voltage level of the driving voltageVD and provides electric charges corresponding to “CL·VD” during thereference period PR, the transmission touch line of the comparativeexample consumes energy corresponding to “CL·VD2.” Only an energy LP2corresponding to “CL·VD2/2” is stored in the load capacitor, and theother energy LP1 corresponding to “CL·VD2/2” is lost due to a lineresistance or the like of the transmission touch line.

Referring to FIGS. 7A and 7C, an energy LP3 corresponding to the“CL·VD2/2” stored in the load capacitor during the reference period PRmay be discharged through a ground after the reference period PR.Referring to FIGS. 7A and 7D, a total energy LP4 lost by applying thetouch driving signal having the driving voltage VD as its highest levelto the transmission touch line during the reference period PRcorresponds to “CL·VD2.”

FIG. 8A is a view showing a waveform of a touch driving signal during areference period according to some exemplary embodiments. FIG. 8B is aview showing a loss amount of electric charges in a transmission touchline due to the touch driving signal of FIG. 8A as a function of acharge amount of a load capacitor according to some exemplaryembodiments. FIG. 8C is a view showing an amount of electric chargesdischarged from the load capacitor due to the touch driving signal ofFIG. 8A according to some exemplary embodiments. FIG. 8D is a viewshowing a sum of a loss amount of electric charges in the transmissiontouch line due to the touch driving signal of FIG. 8A and the amount ofthe electric charges discharged from the load capacitor according tosome exemplary embodiments.

The touch driving signal SG2 during a reference period PR shown in FIG.8A may have substantially the same waveform as that of the second touchdriving signal SG2 during the fourth period PR4 to the seventh periodPR7 shown in FIG. 6. In FIGS. 8B to 8D, “CL” denotes the capacitance ofthe second load capacitor CL2.

Referring to FIGS. 4, 6, 8A, and 8B, since the second touch drivingsignal SG2 has a voltage level of VD/4 (e.g., the second level V2) andprovides electric charges corresponding to “CL·VD/4” during the fourthperiod PR4, the second transmission touch line TX2 consumes an energycorresponding to “CL·VD2/16.” Only an energy corresponding to“CL·VD2/32” is stored in the second load capacitor CL2, and the otherenergy corresponding to “CL·VD2/32” is lost due to a line resistance orthe like of the second transmission touch line TX2. Similarly, duringeach of the fifth to seventh periods PR5 to PR7, only the energycorresponding to “CL·VD2/32” is stored in the second load capacitor CL2,and the other energy corresponding to “CL·VD2/32” is lost due to a lineresistance or the like of the second transmission touch line TX2. InFIG. 8B, an electric charge loss amount LS1 in the second transmissiontouch line TX2 is “CL·VD2/8”, and an energy LS2 stored in the secondload capacitor CL2 is “CL·VD2/2.”

Referring to FIGS. 4, 6, 8A, and 8C, the energy corresponding to“CL·VD2/32” stored in the second load capacitor CL2 during the fourthperiod PR4 may be discharged through the ground. Similarly, the energycorresponding to “CL·VD2/32” may be discharged during each of the fifthto seventh periods PR5 to PR7. The energy corresponding to “CL·VD2/16”may be recycled through the capacitor devices CAP1 and CAP2 during thefifth period PR5. The energy corresponding to “6CL·VD2/16” may berecycled through the capacitor devices CAP1 and CAP2 during the fifth toseventh periods PR5 to PR7. In FIG. 8C, an energy LS3 discharged fromthe second load capacitor CL2 is “CL·VD2/8”, and an energy LS4 recycledthrough the capacitor devices CAP1 and CAP2 is “6CL·VD2/16.”

Referring to FIGS. 4, 6, 8A, and 8D, an energy lost by applying thesecond touch driving signal SG2 increased by “VD/4” during each of thefourth to seventh periods PR4 to PR7 may be equal to a sum of theelectric charge loss amount of the second transmission touch line TX2and the electric charge amount discharged from the second load capacitorCL2 and may be “CL·VD2/16.” A total energy LS5 lost by applying thesecond touch driving signal SG2 to the second transmission touch lineTX2 during the reference period PR corresponds to “CL·VD2/4.”

According to the display apparatus including the touch driving circuitaccording to various exemplary embodiments, the consumption of theenergy may be reduced by about ¼ (a quarter) when compared to thedisplay apparatus including the touch driving circuit according to thecomparative example described with reference to FIGS. 7A to 7D.

FIG. 9 is a circuit diagram showing a touch driving circuit andtransmission touch lines according to some exemplary embodiments.

In the touch driving circuit TDC1 shown in FIG. 9, the second and fourthswitch devices SW12 and SW14 are omitted from the first switch groupSWA, the seventh and ninth switch devices SW22 and SW24 are omitted fromthe second switch group SWB, and the capacitor devices CAP1 and CAP2 areomitted when compared with the touch driving circuit TDC described withreference to FIG. 4.

The touch driving circuit TDC1 of FIG. 9 may generate a touch drivingsignal having three voltage levels. The touch driving circuit TDC1 mayhave a first level corresponding to a ground level, a second levelcorresponding to a level of the driving voltage VD, and a third levelbetween the first level and the second level.

In the touch driving circuit TDC1 of FIG. 9, a first load capacitor CL1shares electric charges with a second load capacitor CL2 during aspecific period to generate the touch driving signal having threedifferent levels.

In the case that the touch driving circuit TDC1 generates the touchdriving signal having three different levels, the capacitor device shownin FIG. 4 may be omitted.

Referring to FIG. 6 again, a signal having the waveform of the firsttouch driving signal SG1 during the first to ninth periods PR1 to PR9may be referred to as an “in-phase signal,” and a signal having thewaveform of the second touch driving signal SG2 during the first toninth periods PR1 to PR9 may be referred to as an “out-phase signal.”The in-phase signal and the out-phase signal have opposite phases toeach other and are signals delayed by half a period.

As shown in FIG. 3, the transmission touch lines TX1 to TX5 of the touchsensing unit TS are provided in a plural number, and the transmissiontouch lines TX1 to TX5 may be substantially simultaneously driven. In acase that the transmission touch lines TX1 to TX5 are substantiallysimultaneously driven instead of being sequentially driven, the touchdriving signals applied to the transmission touch lines TX1 to TX5 areto be distinguished from each other. The touch driving signal includesthe in-phase signal and the out-phase signal, which are periodicallymixed with each other, and thus, the touch driving signal may bedistinguished from other touch driving signals.

Since the transmission touch lines TX1 to TX5 are substantiallysimultaneously driven, a capacitance of capacitors formed by thetransmission touch lines TX1 to TX5 and the sensing touch lines RX1 toRX4 increases, and thus, a sensitivity of the touch sensing unit T5 maybe improved.

Among the transmission touch lines TX1 to TX5, some transmission touchlines are applied with the in-phase signal, and the other transmissiontouch lines are applied with the out-phase signal. In this case, thenumber of the transmission touch lines applied with the in-phase signalmay be different from the number of the transmission touch lines appliedwith the out-phase signal.

Referring to the fifth period PR5 of FIG. 6 by way of example, in thecase that the number of the transmission touch lines applied with thein-phase signal is greater than the number of the transmission touchlines applied with the out-phase signal, a voltage level formed by thefirst and second transmission touch lines TX1 and TX2 sharing theelectric charges during the fifth period PR5 of FIG. 6 may be greaterthan the third level V3. As an example, in the case that the first tothird transmission touch lines TX1 to TX3 are applied with the in-phasesignal among the transmission touch lines TX1 to TX5 of FIG. 3 and thefourth and fifth transmission touch lines TX4 and TX5 are applied withthe out-phase signal among the transmission touch lines TX1 to TX5 ofFIG. 3, a voltage level formed by the first to fifth transmission touchlines TX1 to TX5 sharing the electric charges during the fifth periodPR5 may be greater than the third level V3.

On the contrary, in the case that the number of the transmission touchlines applied with the in-phase signal is smaller than the number of thetransmission touch lines applied with the out-phase signal, a voltagelevel formed by the first and second transmission touch lines TX1 andTX2 sharing the electric charges during the fifth period PR5 of FIG. 6may be smaller than the third level V3. As an example, in the case thatthe first and second transmission touch lines TX1 and TX2 are appliedwith the in-phase signal among the transmission touch lines TX1 to TX5of FIG. 3 and the third to fifth transmission touch lines TX3 to TX5 areapplied with the out-phase signal among the transmission touch lines TX1to TX5 of FIG. 3, the voltage level formed by the first to fifthtransmission touch lines TX1 to TX5 sharing the electric charges duringthe fifth period PR5 may be smaller than the third level V3.

As described above, the voltage level of the first transmission touchline TX1 may be different from the voltage level of the secondtransmission touch line TX2 in the periods each in which the firsttransmission touch line TX1 shares the electric charges with the secondtransmission touch line TX2 due to the difference in number between thetransmission touch lines to which the in-phase signal is applied and thetransmission touch lines to which the out-phase signal is applied.

FIG. 10 is a waveform diagram showing a waveform of a touch drivingsignal according to according to some exemplary embodiments.

Referring to FIG. 10, there is a first difference Vt between a voltagelevel of a first period PD1, in which a first transmission touch lineTX1 of a touch driving signal SGC shares electric charges with a secondtransmission touch line TX2, and a voltage level of a second period PD2.

FIG. 11 is a waveform diagram showing a waveform of a touch drivingsignal according to according to some exemplary embodiments.

A touch driving signal SGD according to some exemplary embodiments mayhave opposite phases to each other during different phase periods fromeach other.

The touch driving signal SGD has an in-phase signal during a first phaseperiod PK1, and the touch driving signal SGD has an out-phase signalduring a second phase period PK2.

The touch driving signal SGD shown in FIG. 11 may be applied to each ofthe first and second touch driving signals SG1 and SG2 described withreference to FIG. 6.

Although certain exemplary embodiments and implementations have beendescribed herein, other embodiments and modifications will be apparentfrom this description. Accordingly, the inventive concepts are notlimited to such embodiments, but rather to the broader scope of thepresented claims and various obvious modifications and equivalentarrangements.

What is claimed is:
 1. A display apparatus comprising: a display panel;a touch sensing unit disposed on the display panel, the touch sensingunit comprising a first transmission touch line and a secondtransmission touch line spaced apart from the first transmission touchline; and a touch driving circuit configured to: apply a first touchdriving signal to the first transmission touch line; and apply a secondtouch driving signal to the second transmission touch line, wherein thetouch driving circuit comprises: a first switch group comprising a firstsharing switch device of which a first end is connected to the firsttransmission touch line; and a second switch group comprising a secondsharing switch device of which a first end is connected to the secondtransmission touch line and a second end is connected to a second end ofthe first sharing switch device, and wherein the touch driving circuitis configured to: turn on the first sharing switch device and the secondsharing switch device during a first period such that the first touchdriving signal and the second touch driving signal have a first voltagelevel; and turn on the first sharing switch device and the secondsharing switch device during a second period different from the firstperiod such that the first touch driving signal and the second touchdriving signal have a second voltage level different from the firstvoltage level.
 2. The display apparatus of claim 1, wherein: the touchsensing unit further comprises a third transmission touch line spacedapart from the first and second transmission touch lines; the touchdriving circuit is configured to apply a third touch driving signal tothe third transmission touch line; the touch driving circuit comprises athird switch group comprising a third sharing switch device of which oneend is connected to the third transmission touch line and a second endis connected to the second ends of the first and second sharing switchdevices; and the touch driving circuit is configured to: turn on thethird sharing switch device during the first period such that the thirdtouch driving signal has the first voltage level; and turn on the thirdsharing switch device during the second period such that the third touchdriving signal has the second voltage level.
 3. The display apparatus ofclaim 2, wherein: the first and second touch driving signals have afirst phase during the first period; and the third touch driving signalhas a second phase different from the first phase during the firstperiod.
 4. The display apparatus of claim 3, wherein: the first touchdriving signal has the first phase during the second period; and thesecond and third touch driving signals have the second phase during thesecond period.
 5. The display apparatus of claim 1, wherein: the firstswitch group further comprises: a first upper switch device comprising afirst end connected to the first transmission touch line; and a firstlower switch device comprising a first end connected to the firsttransmission touch line; and the touch driving circuit furthercomprises: a first capacitor device comprising one electrode connectedto a second end of the first lower switch device; and a second capacitordevice comprising one electrode connected to a second end of the firstupper switch device.